Armed with “eight key issues” and guarantees of at least $15 million in funding, Westchester County Executive Rob Astorino has decided to run for governor, but will put off the announcement for another week, The Post has learned.

Astorino, 46, had pledged to make an announcement no later than the end of February — this coming Friday — but for tactical reasons has decided to put off the statement until the first week in March, probably next Monday or Tuesday, GOP sources said.

The sources said the Republican executive, who won a landslide re-election victory in November in his 2-1 Democratic county, made the final decision to enter the governor’s race in the past few days after receiving commitments of at least $15 million in campaign contributions — and guarantees of much more if he closes the gap in an uphill battle against Gov. Cuomo, who will likely have $40 million-plus to spend.

“There’ll be a lot of independent expenditure money from across the country against Cuomo if Rob can make the race tight,’’ said a source close to Astorino.

Astorino’s challenge to Cuomo will be built around what are being called “eight key issues’’ that polling has shown to be of real importance to voters. They are:

Cuomo’s capitulation to what an adviser called “radical Luddite environmentalists’’ by refusing to approve natural-gas drilling in the economically depressed Southern Tier region near Pennsylvania, where job-creating “fracking’’ has been under way for years.

Cuomo’s explosive declaration that “extreme conservatives,’’ defined as individuals who are anti-abortion, anti-same-sex marriage, and pro-gun rights, have “no place in New York.’’

Upstate opposition to the governor’s anti-gun ownership “Safe Act,’’ which has been condemned in resolutions passed by all but two upstate counties.

The governor’s “Cuomo U’’ plan for free college education for state prison inmates, a proposal that has enraged many voters. “This will be a huge campaign issue,’’ said a close Astorino aide.

Fears, especially in the suburbs, over Mayor de Blasio’s class-warfare rhetoric and his closeness to public-employee unions. While Cuomo is at odds with de Blasio over higher taxes on the wealthy, “Cuomo, as head of the Democratic Party, is answerable for de Blasio’s actions,’’ said the Astorino aide.

Uneasiness over ObamaCare, which Cuomo has embraced, and concern, especially among Jewish voters, over President Obama’s Middle East policies.

Cuomo’s use of tens of millions of dollars in public funds on a national TV campaign supposedly promoting a business-friendly climate but widely seen as designed to boost Cuomo’s popularity.

“Let’s put it this way, there are no shortages of issues to use against Gov. Cuomo,’’ is how one Astorino aide summed up the planned campaign.

Donald Trump, who says he’ll run for governor if the GOP unites around him, is being urged by an important but skeptical backer to begin acting more like a real candidate.

“Trump really needs to start to take actions like a candidate to keep the enthusiasm he has amongst county chairs,’’ said the leading Republican.

“He needs to travel and do more events upstate and on Long Island.’’

A big test of Trump’s interest will come shortly when state GOP Chairman Ed Cox convenes a series of regional candidate screenings for potential statewide candidates.

“It’ll be telling if Trump makes himself available for those,’’ said the influential Republican.

Trump last week told The Post that he would soon set up a legally required campaign committee, an important step in beginning a candidacy.